This invention relates to a method and apparatus for controlling predetermined operating conditions of a machine and, more particularly, to the use of a programmed processor, such as a microprocessor, to control the operating conditions of a dictation/transcription machine in response to the actuation of selected switches.
In recording/reproducing devices, such as dictation/transcription machines, which are commercially available, various operating modes and conditions are selected by the manual operation of particular selector switches. Depending upon which switch is actuated, a corresponding condition is established. When that same switch is deactuated, the condition is terminated. The control over such modes of operation, such as the priority by which certain modes are established, heretofore has been effected by way of so-called "ladder" networks, discrete control circuits, and the like.
The use of "hardware" implementation to control machine operations, that is, the use of the aforementioned ladder networks and discrete control circuitry, may be expensive to construct and assemble and, moreover, may be subjected to an unsatisfactorily high proportion of malfunction. The present invention substitutes a single microprocessor for multiple control circuits and switching devices which have been relied upon heretofore. Not only does the use of such a microprocessor improve reliability and lower the overall cost of the dictation/transcription machine, but the well-known capabilities and flexibility of microprocessors are turned to account in that additional, advantageous features may be provided. For example, control over the power supply to the dictation/transcription machine may be obtained, regardless of whether a simple power switch is operated, or whether an accessory power switch is operated, or whether a cradle switch is operated, or whether an electronic power control signal is produced. The interaction of such switches and signals is controlled by the microprocessor to effect a suitable supply or termination of power. As another example, this same microprocessor is used to establish a particular mode of operation, such as a telephone mode, whereby dictated information that is received from a telephone network is recorded on the record medium by the dictation/transcription machine. Various ancillary conditions which are necessary for carrying out such an operation are controlled by the microprocessor, even when only a single selector switch is operated.